1. Field of the Invention
The present invention relates to a device for driers for compressed air and provided to change the communication between an inlet pipe and exhaust pipe on one hand and a first outlet pipe and a second outlet pipe on the other hand, which inlet emanates from a pressure source and which exhaust pipe is in communication with the free atmosphere, and which first outlet pipe is in communication with a first connected element of the drier as a first drying receptacle and which second outlet pipe is in communication with a second element as a second drying receptacle, the device being provided in a first functioning condition to connect the inlet with the first outlet and the second outlet with the exhaust pipe and in a second functioning condition to connect the inlet with the second outlet and the first outlet with the exhaust pipe under influence of power impulses.
2. Description of the Prior Art
The compressed air supplied by a compressor plant generally contains water. This water can give rise to serious drawbacks in connection with the use of the compressed air as for example disturbances in the function of the valves and accumulation of liquid in apparatuses and instruments, which can bring about malfunctions, and in case of congealation of the water such malfunctions can be of very serious nature. In systems driven by compressed air comprising valves, instruments and other delicate components it is therefore the usual thing to provide a drier for the compressed air. A known type of such a drier comprises two receptacles, which contain a water adsorbing or absorbing agent as for example silica gel. These two receptacles are alternatively connected to the current of air from the compressor plant, the liquid contents of the air thereby being taken up by said content of the receptacle. After a certain period of time, which is not greater than that the contents of the receptacle still can be calculated to have a remaining liquid absorbing capacity, the other receptacle is connected. This second receptacle during the period of time, when the first receptacle has been connected, has been aerated, so that in any case the main quantity of earlier absorbed liquid has been driven out of the liquid absorbing contents of the receptacle. After the second receptacle has been connected to the current of air, an aerating of the first mentioned receptacle takes place and so on in a continuously repeated cycle. The aerating can be made by forcing a small quantity of the produced and dried compressed air through the receptacle in turn to be aerated. As an alternative a separate fan installation can be provided for the aerating and then be alternatively connected to the two receptacles.